1. Field of the Invention:
This invention relates to an apparatus for controling a pulse generator, such as a pulse generator provided in a printer for generating a printing timing pulse.
2. Description of the Prior Art:
There is a printer which comprises a platen having a plurality of longitudinally extending projections on its outer peripheral surface, and a printing hammer which is movable longitudinally of the platen. The motion of the printing hammer is controlled by a printing timing pulse synchronized with the position of a particular projection on the platen. In order to form an accurately positioned dot, it is necessary to control the phase of any such printing timing pulse. The pulse is generated by a sensor which cooperates with a rotary detecting plate. The sensor is movable to a predetermined extent about the center of the detecting plate. The adjustment of the sensor is effected by loosening a screw for the sensor, displacing the sensor along a guide and tightening the screw again. The necessity for loosening the screw and tightening it again requires a lot of time for the adjustment of the sensor, and makes it a very inefficient job. A large space is required for installing the optical sensor movably around the outer periphery of the rotary detecting plate, and the entire apparatus is, therefore, very large. The sensor is movable only to a limited extent, and sometimes fails to control the printing position. In any such event, it is necessary to change the engagement of a motor pinion, a train of reduction gears and a platen gear. This change requires the use of special jigs, and is, therefore, a costly job. Moreover, it is a complicated job to establish a predetermined relationship between the projections on the platen and the detecting holes in the rotary detecting plate.